With the development of industrial equipment, electric railroads and automobiles, operation temperatures of semiconductor elements which are used for them have been increased. Recently, development for semiconductor elements which operate even at high temperatures has been carried out energetically, and reduction in the size, increase in the withstand voltage and increase in the current density of the semiconductor elements has been progressed. Particularly, wide band gap semiconductors such as SiC, GaN, etc. have a larger band gap than that of Si semiconductors. Therefore, increase in the withstand voltage, reduction in the size, increase in the current density, and operation at high temperatures of semiconductor devices has been expected. In order to produce a device by using the semiconductor element having the above-mentioned features, even in a case where the semiconductor element operates at a temperature higher than 150 degrees Celsius, it is necessary to secure stable operation of the semiconductor device by suppressing formation of a crack on a bonding material and degradation of wirings.
On the other hand, as a method for sealing a semiconductor element with a resin in a semiconductor device, Patent Document 1 proposes a method in which a dam material is used to enclose the periphery of a semiconductor element so as to seal a part of its inside with a resin. Further Patent Document 2 proposes a method in which a dam is formed in the periphery of a semiconductor element for stopping the flow of a resin which covers the semiconductor element.